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Bone Age is the degree of maturation of a child’s bones. It can be less, or more than your child’s chronological age, or it can be about the same. 

• Girls are 99% done growing in height when their bone age reaches 15, and boys are 99% done growing in height when their bone age reaches 17 years.* 

• If you don’t know your child’s bone age, you can’t know how much growth they have left. Period. 

• And without an X-ray of the left hand, and a bone-age calculation, it is a wild guess.

Your pediatrician is using an old study from the 1950’s that says a child’s average height is the average of Mom’s and Dad’s height plus three inches for a boy, and minus 3 inches for a girl. Works great if you have a thousand children, that would be the average, but you likely are not having a thousand children! 

Family of Four: Case Study using Pediatrician Model 

Mom and Dad Average = 5’ 7.5” 

Pediatrician Model Boy = 5’ 10.5” 

Pediatrician Model Girl = 5’ 4.5” 

Boy 1 Actual Adult Height = 6’ 0.5” 

Boy 2 Actual Adult Height = 5’ 6.5” 

Girl 1 Actual Adult Height = 5’ 2” 

Boy 3 Actual Adult Height = 5’ 9.5” 

Only one of four children came within an inch of the pediatrician’s guess, and one was four inches off!


 * Strauss, Barbieri (13 September 2013). Yen and Jaffe’s Reproductive Endocrinology.

ISBN 9781455727582. Retrieved 5 July 2020.